When I used composer to get Translator for my Behat installation the I found line 131 missing a semi-colon. The original function looks like this:

public function setFallbackLocale($locales)
{
$this->setFallbackLocales(is_array($locales) ? $locales : array($locales))
}

I added a semi-colon to the line and everything works well. The line should look like the following:
$this->setFallbackLocales(is_array($locales) ? $locales : array($locales));